NUMA, A NUCLEAR-PROTEIN INVOLVED IN MITOSIS AND NUCLEAR REFORMATION

NuMA, a nuclear protein that associates with the mitotic apparatus, wa s identified in 1980 as a high molecular weight component of the nucle ar matrix with the unusual property of associating with the microtubul es of the spindle apparatus during mitosis. Over the past two years, a burst of interest in this intriguing protein has led to the clear doc umentation of its cell cycle redistribution, determination of its prim ary sequence, elucidation of its cell cycle dependent targeting domain s, as well as disruption of its function through antibody microinjecti on and expression of dominant-negative mutants. Together, these data s upport a central role for NuMA in both mitotic-spindle dynamics and th e reformation of the daughter cell nuclei at the end of mitosis.